Field of the Invention
Embodiments of the invention relate to memory devices, and more particularly to memory devices with memory cells having sidewall dielectrics.
Description of the Related Art
A wide variety of computer memory devices are now available. One type of memory device that has become popular is flash memory. Flash memory devices advantageously are nonvolatile and do not require capacitors as storage devices. Because fewer components are required in flash memories, a higher density of cells may be formed.
A flash memory cell typically includes a charge trapping structure (sometimes also referred to as a charge retention structure, a charge storage structure, or a storage area, for example) and a control gate. The control gate is configured to selectively inject and remove the charge in the charge trapping structure. The control gate is usually positioned adjacent to the charge trapping structure but separated from the charge trapping structure by a dielectric. When a voltage is applied to the control gate, charge may tunnel through the dielectric and be stored in the charge trapping structure. The state of charge stored in the charge trapping structure is indicative of the logical state of the flash memory cell.
There is a continual demand to produce flash memories with memory cells that are smaller in size to allow for higher memory capacities. However, as the dimensions of the flash memory cells decrease, new problems are introduced and old problems are exacerbated. For example, poor charge trapping characteristics may cause a flash memory cell to indicate an incorrect logical state. Thus, there is a need for flash memories and methods of forming those memories that have, for example, good reliability in indicating a desired logic state.